Helmet



FIG. 1 is a perspective view of a helmet showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a top plan view thereof.

The broken lines of FIGS. 1-7 are illustrative of the visible environmental structure of the helmet and form no part of the claimed design. 

CLAIM The ornamental design for a helmet, as shown and described. 